building an electric telegraph

i want to build an electric telegraph that will look like this:

what i need:

2 pieces of wood.
9 small nails.
2 large iron nails.
4 flat strips of metal.
20ft or more of insulated wire.
2 batteries.

the key:

is made by screwing one of the strips of metal to one of the pieces of wood so that pushing down on the strip brings the strip into electrical contact with the screw that is mounted under it.

the battery holder is made by screwing two of the metal strips to the wood so that they can make electrical contact with each end of the line up of the two batteries. a rubber band can be used to maintain pressure on the battery contacts.

the sounder is the tricky bit. it requires a bit of care in construction and adjustment.

the electromagnet coil consists of one of the iron nails with at least 100 turns of the wire wound neatly around it. ( if possible wind on 200 turns to make the magnetic force stronger. )

the longer iron-bearing strip of metal is screwed to the wooden base and bent so that it extends up and over the top of the nail. this piece has been labeled "IRON-BEARING" in the parts photograph to indicate that it is pulled in by the magnet. many food cans are made of this type of metal. be careful not to cut yourself on any sharp edges.

when the electric current passes through the coil of wire, it makes the nail into an electromagnet which pulls the strip of metal down to the nail and makes a clicking sound. (you may have to carefully adjust the strip of metal so it is close enough to the nail allow it to be pulled down by the magnet.)

the second nail is important because it keeps the strip of metal from pulling too far away from the electromagnet. it also serves to make a clicking sound when the strip of metal is released by the magnet and moves upward.

you can learn to tell the difference between the dots and the dashes of the morse code by learning to tell the difference between the pull-in "click" and the release-"clack".

the pull-in "click" is the sound the metal strip makes when it is pulled in by the electromagnet coil and strikes the nail which is in the center of the coil.

the release "clack" is the sound that the metal strip makes when it is no longer pulled by the electromagnet coil and it moves rapidly upward to strike the upper nail.


here is a list which shows the dot and dash equivalents of letters and numbers in the original morse code (american morse code), and the continental (international) code.

( DOT = * DASH = - LONG DASH = ---- )


MORSE CODE CONTINENTAL CODE
CHARACTER: AMERICAN MORSE INTERNATIONAL CODE

A * - * -
B - * * * - * * *
C * * * - * - *
D - * * - * *
E * *
F * - * * * - *
G - - * - - *
H * * * * * * * *
I * * * *
J - * - * * - - -
K - * - - * -
L ---- * - * *
M - - - -
N - * - *
O * * - - -
P * * * * * * - - *
Q * * - * - - * -
R * * * * - *
S * * * * * *
T - -
U * * - * * -
V * * * - * * * -
W * - - * - -
X * - * * - * * -
Y * * * * - * - -
Z * * * * - - * *

1 * - - * * - - - -
2 * * - * * * * - - -
3 * * * - * * * * - -
4 * * * * - * * * * -
5 - - - * * * * *
6 * * * * * * - * * * *
7 - - * * - - * * *
8 - * * * * - - - * *
9 - * * - - - - - *
0 ------ - - - - -

Period * * - - * * * - * - * -
Comma * - * - - - * * - -
Question - * * - * * * - - * *


i like the idea of mounting a pencil on the sounder arm and have it mark a piece of paper with either a high mark or a low mark while the paper was pulled under the pencil at an approximately constant speed. this would approximate samual morse's very first telegraph systems used before people learned to copy code by ear. morse invented a "register" which used a clockwork mechanism to pull a paper tape under a pencil which was moved in and out by an electromagnet.

you can then translate the short downwards pencil marks on the paper as dots... and the long downwards pencil marks on the paper as dashes...